This does correlate to some research I did 15 years ago. Set it and forget it. Heat pumps operate most efficiently when holding a steady temperature. Turning heat pumps down when you’re away or asleep may actually use more energy than leaving them on. The reason is that they have to work harder to come back to the desired temperature than they do to maintain it. It’s best to set them at a comfortable temperature and forget it. Adjusting the temperature for short periods of time, such as overnight, will not save money with heat pumps. Here's another blurb from https://www.bogleheads.org/forum/viewtopic.php?t=156549 Heat pump - drop temperature at night or keep constant? Lower it at night but have a more gradual temp rise in the morning. If all of a sudden the thermostat gives an instantaneous temp increase of 5 degrees that will kick on the aux heat. But if it's 2 degrees higher or might not. Then 30 minutes later go another 2 degrees. Slowly work up to your desired morning temp. If it's really cold outside and the heat pump can't keep up anyways, then nothing will stop the aux heat from turning on. I have a Nest that can be scheduled for smaller increments. I now have natural gas furnace and dedicated AC and LOVE it.